The role that the utilization of dental services plays in modifying the progression of periodontal disease in adults is not known. Increased access to dental services may have paradoxical effects; it may be associated with an increase in disease. These effects may be due to the so-called "discovery effect", where increased utilization translates into increased detection of previously undiagnosed disease. On the other hand, to the extent that periodontal services are effective, we would expect that increased service use would decrease the prevalence or the severity and extent of periodontal disease (or slow the progression of the disease). In response to an invited presentation at a conference on risk factors of periodontitis (to be held in 1993), NIDR staff is examining the effects utilization has on various measures of periodontal disease using several cross-sectional and longitudinal data bases. Preliminary analyses (on the VA longitudinal data base) and an extensive literature review have been conducted in 1992.